Magnetic head having write head with helical coil and method for fabrication thereof

ABSTRACT

The present invention is a magnetic head having a helical induction coil and includes hard disk drive devices that utilize the magnetic head. The helical coil is fabricated around a magnetic pole yoke in a series of process steps that include a reactive ion etch (RIE) process step which is utilized to simultaneously form vertical interconnect vias and upper helical coil member trenches. Thereafter, in a single fabrication step, such as by electroplating, the vertical interconnect lines and the upper helical coil traces are created in a single fabrication step, such that they are integrally formed. The vertical interconnect lines provide an electrical connection between outer ends of previously formed lower helical coil traces and outer ends of the integrally formed upper helical coil traces, such that a helical coil is fabricated. In the preferred embodiment, the helical coil is composed of copper.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to magnetic heads thatare utilized with thin film hard disk data storage devices, and moreparticularly to the design and fabrication of helical induction coilsthat are utilized in the write head components of such magnetic heads.

[0003] 2. Description of the Prior Art

[0004] The ongoing efforts to develop magnetic heads having increaseddata writing rates are impacted by the design of the induction coilsthat are utilized to generate the magnetic flux of the write head. Whilethe flat, spiral induction coils of prior art magnetic heads have beenadequate, the overall length of the spiral induction coil element has arelatively high resistance and/or inductance which becomes problematicat high frequencies, as well as creating unwanted magnetic head heatingdue to the passage of current through the relatively high resistancecoil element. Additionally, the footprint of the flat spiral coil isrelatively large. This large footprint poses difficulties in placingelements close together to realize large scale integration.

[0005] To solve some of these problems, helical coils have beendeveloped. Such coils are fabricated to wrap around the magnetic poleyoke. However, fine pitch helical coils are generally more difficult tofabricate than the prior art flat spiral coils. The present inventionincludes a magnetic head having a helical coil and a method forfabricating the helical coil that produces a finer pitch helical coilwith fewer, simple fabrication steps than the prior art helical coils.

SUMMARY OF THE INVENTION

[0006] The present invention is a magnetic head having a helicalinduction coil and includes hard disk drive devices that utilize themagnetic head. The helical coil is fabricated around a magnetic poleyoke in a series of process steps that include a reactive ion etch (RIE)process step which is utilized to simultaneously form verticalinterconnect vias and upper helical coil member trenches. Thereafter, ina single fabrication step, such as by electroplating, the verticalinterconnect lines and the upper helical coil traces are created in asingle fabrication step, such that they are integrally formed. Thevertical interconnect lines provide an electrical connection betweenouter ends of previously formed lower helical coil traces and outer endsof the integrally formed upper helical coil traces, such that a helicalcoil is fabricated. In the preferred embodiment, the helical coil iscomposed of copper.

[0007] It is an advantage of the magnetic head of the present inventionthat a hard disk drive incorporating the magnetic head can be moreeconomically manufactured.

[0008] It is another advantage of the magnetic head of the presentinvention that it includes a fine pitch helical induction coil that issimpler and easier to fabricate.

[0009] It is a further advantage of the magnetic head of the presentinvention that it includes a helical induction coil that includesvertical interconnect lines and upper helical coil traces that areintegrally formed.

[0010] It is yet another advantage of the magnetic head of the presentinvention that vertical vias and upper helical coil trenches arefabricated in a single fabrication process step, such that thefabrication of the helical coil is simplified.

[0011] It is an advantage of the fabrication method of the magnetic headof the present invention that a single fabrication step is utilized tocreate vertical interconnect vias and upper helical coil trenches, suchthat alignment problems of these components are eliminated.

[0012] It is another advantage of the fabrication method of the magnetichead of the present invention that the vertical interconnect lines andthe upper helical coil traces are integrally formed in a singlefabrication step, such that only one metallization step is required.

[0013] These and other features and advantages of the present inventionwill no doubt become apparent to those skilled in the art upon review ofthe following detailed description which makes reference to the severalfigures of the drawings.

IN THE DRAWINGS

[0014]FIG. 1 is a is a side cross-sectional view schematically depictinga process step in the fabrication of prior art magnetic heads;

[0015]FIGS. 2 and 3 depict a first process step in the fabrication ofthe helical induction coil of the present invention, wherein FIG. 2 is atop plan view of the device, and FIG. 3 is a side cross-sectional viewtaken along lines 3-3 of FIG. 2;

[0016]FIG. 4 is a side cross-sectional view taken along identical linesas FIG. 3, depicting a further process step of the present invention;

[0017]FIGS. 5 and 6 depict a further process step of the presentinvention, wherein FIG. 5 is a top plan view of the device, and FIG. 6is a side cross-sectional view taken along lines 6-6 of FIG. 5;

[0018]FIGS. 7 and 8 depict a further process step of the presentinvention, wherein FIG. 7 is a top plan view of the device, and FIG. 8is a cross-sectional view taken along lines 8-8 of FIG. 7;

[0019]FIGS. 9 and 10 depict yet a further fabrication step of thepresent invention, wherein FIG. 9 is a top plan view of the device, andFIG. 10 is an end cross-sectional view taken along lines 10-10 of FIG.9;

[0020]FIGS. 11, 12 and 13 depict a further process step of the presentinvention, wherein FIG. 11 is a top plan view, FIG. 12 is a sidecross-sectional view taken along lines 12-12 of FIG. 11, and FIG. 13 isan end cross-sectional view taken along lines 13-13 of FIGS. 11 and 12;

[0021]FIGS. 14 and 15 depict a further process step of the presentinvention, wherein FIG. 14 is an end cross-sectional view taken alongidentical lines as FIG. 13, and FIG. 15 is a side cross-sectional viewtaken along identical lines as FIG. 12;

[0022]FIGS. 16, 17 and 18 depict a further process step of the presentinvention, wherein FIG. 16 is a top plan view, FIG. 17 is a sidecross-sectional view taken along lines 17-17 of FIG. 16, and FIG. 18 isan end cross-sectional view taken along lines 18-18 of FIGS. 16 and 17;

[0023]FIGS. 19, 20 and 21 depict a further process step of the presentinvention, wherein FIG. 19 is a side cross-sectional view taken alonglines 19-19 of FIG. 20, FIG. 20 is a top plan view, and FIG. 21 is across-sectional view taken along skewed lines 21-21 of FIG. 20;

[0024]FIGS. 22 and 23 depict a further process step of the presentinvention, wherein FIG. 22 is a top plan view, and FIG. 23 is across-sectional view taken along skewed lines 23-23 of FIG. 22; and

[0025]FIG. 24 is a simplified top plan view of a hard disk drive deviceincluding the magnetic head of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The magnetic head of the present invention is suitable for usewith well known hard disk drive devices. A significant feature of themagnetic head of the present invention is the helical induction coilthat is fabricated around the yoke portion of the second magnetic pole.The fabrication steps described herebelow produce a fine pitched helicalcoil that is simpler and easier to manufacture than prior art helicalcoils.

[0027]FIG. 1 is a side, cross sectional view of a process step in thefabrication of magnetic heads that is well known in the prior art andwill serve as a starting point in the description of the presentinvention. As depicted in FIG. 1, the fabrication of the magnetic head10 includes a slider substrate base 14 having a first read shield (S1)layer 18 deposited thereupon. Insulation layers 22 with a read headelement 26 fabricated therewithin are formed upon the S1 shield layer18. Thereafter, a second read head shield (S2) layer 30 is formed uponthe insulation layers, followed by another insulation layer 34 and afirst write head magnetic pole (P1) layer 38. In well known alternativehead design, termed a merged head, a single layer serves the dualpurpose of the S2 and P1 layers; that is, the single layer serves asboth a read head shield and a first write head magnetic pole. Thepresent invention is suitable for use with either type of magnetic headdesign. A write head gap layer 44 is thereafter deposited upon the P1layer. The fabrication steps of the present invention are next describedcommencing with FIGS. 2 and 3.

[0028]FIG. 2 is a top plan view depicting the next fabrication steps,and FIG. 3 is a cross-sectional view of the device depicted in FIG. 2taken along lines 3-3 of FIG. 2. As depicted in FIGS. 2 and 3, a P2 poletip 60, generally composed of NiFe 45/55, is fabricated upon the writegap layer 44 in a fabrication step that is well known to those skilledin the art. Also fabricated upon the write gap layer 44 are a pluralityof lower traces 64 of the helical coil. The lower coil traces 64 arefabricated photolithographically and plated up with copper, and atantalum/copper seed layer is preferably first deposited to facilitatethe plating of the copper bottom coil traces 64. Following the removalof the photoresist, an insulator material 68, such as Al₂O₃ isdeposited, and this step is followed by a chemical mechanical polishing(CMP) step which results in a flat top surface 72. Thereafter, asdepicted in FIG. 4, a second layer 80 of insulator material is depositedupon the polished surface 72 of the device. The insulator layer ispatterned such that the upper surface 84 of the P2 pole tip 60 isexposed. The insulator material of layer 80 can be Si02 or a thermallystable polymer. Thereafter, as depicted in FIGS. 5 and 6, usingwell-known photolithographic techniques, a yoke 88 is fabricated on topof the insulator layer 80, such that a good electromagnetic connectionis made between the yoke 88 and the P2 pole tip 60 at the P2 pole tipsurface 84. Significantly the width w of the yoke is less than thelength of the lower helical coil traces, as can best be seen in FIG. 5such that the outer ends 92 of the lower helical coil traces 64 projectoutwardly beyond the lateral edges 96 of the yoke.

[0029] Thereafter, as is depicted in FIGS. 7 and 8, a further layer ofinsulator material 100 preferably utilizing the same material that hasbeen utilized in insulator layer 80, is deposited upon the upper surfaceof the device. This step is followed by a second CMP step as depicted inFIGS. 9 and 10, to produce a flat upper surface 108 which exposes theyoke surface 112 and retains the insulator material 100 along the sides96 of the yoke 88, as is best seen in FIG. 10. Thereafter, as depictedin FIGS. 11, 12 and 13, a patterned etch stop layer 120 is depositedupon the yoke surface 112. As is best seen in FIGS. 11 and 13, the widthv of the etch stop layer 120 is sufficient to cover the yoke surface112, however the outer ends 92 of the lower helical coil traces extendbeyond the outer edges 124 of the etch stop layer 120. The etch stoplayer 120 is fabricated from a material which has significantly greaterresistance to a reactive ion etch (RIE) process than the materialutilized to fabricate the insulator layers 80 and 100. Therefore, wherethe insulator layers 80 and 100 are composed SiO₂, an aluminum oxideetch stop layer 120 is fabricated; whereas, if the insulator layers 80and 100 are composed of a polymer composition, the etch stop layer 120can be composed of either SiO₂ or aluminum oxide. Of course, anappropriate etchant species is utilized in the following RIE etchingstep as is described herebelow.

[0030] As is depicted in FIGS. 14 and 15, following the deposition ofthe patterned etch stop layer 120, a further layer of insulator material130 is deposited upon the device, covering the etch stop layer 120 andextending beyond the ends 92 of the lower helical coil traces whichproject outside of the etch step layer 120. Thereafter, as depicted inFIGS. 16, 17 and 18, a suitable patterned RIE mask 140 is fabricatedupon the upper insulator material layer 130. The RIE mask is patternedto include opening 144 for upper helical coil traces in alignment withthe lower helical coil traces previously fabricated, such that the outerends 148 of the openings 144 for the upper helical coil traces aredisposed above the projecting ends 92 of the previously fabricated lowerhelical coil traces 64.

[0031] An RIE etch step is next performed through the RIE mask 140, asis depicted in FIGS. 19, 20 and 21. The RIE etching proceeds downwardthrough the insulator layer 130 forming upper helical coil trenches 160until it encounters the etch stop layer 120. However, as indicatedhereabove, the outer ends 148 of the openings for the upper helical coiltraces of the RIE mask extend laterally beyond the edges 124 of the etchstop layer 120. In these outer edge portions 148 of the mask's openings144, the RIE etching continues downwardly through the insulation layers130, 100 and 80, forming vertical interconnect vias 164, until the outerprojecting ends 92 of the lower helical coil traces 64 are encountered.The etched RIE pattern thus includes both the upper helical coiltrenches 160 and the downward coil interconnect vias 164.

[0032] Thereafter, as is depicted in FIGS. 22 and 23, a seed layer 170,preferably composed of tantalum/copper, is deposited into the coiltrenches 160 and vias 164, which is followed by the electroplating ofcopper helical coil elements into the trenches 160 and vias 164, platingup both the vertical interconnect lines 180 and the upper helical coiltraces 184. It is therefore to be understood that at the completion ofthe copper plating step that the lower coil traces 64 are electricallyinterconnected with the upper coil traces 184 through the verticalcopper interconnect lines 180, such that the helical coil is essentiallyfabricated. A CMP step is next performed to clean up the excess platedcopper from the electroplating step, such that the upper helical coiltraces are independently well defined. Subsequent process steps that arewell known in the art, are then performed and the magnetic head 200 ofthe present invention is encapsulated and completed.

[0033] The magnetic head 200 of the present invention is utilized toread and write data to magnetic media, such as hard disks in hard diskdrive devices. A simplified top plan view of a hard disk drive 210 ispresented in FIG. 24, wherein at least one hard disk 212 is rotatablymounted upon a motorized spindle 214. A slider 216, having a magnetichead 200 formed thereon, is mounted upon an actuator arm 218 to flyabove the surface of each rotating hard disk 212, as is well known tothose skilled in the art. The magnetic head 200 of the present inventionenables the hard disk drive to write data to the hard disk at a fasterdata writing rate due to the helical coil configuration of the magnetichead 200. Because the magnetic head 200 is easier and less expensive tofabricate, the hard disk drive 210 with the magnetic head 200 is moreeconomical to manufacture.

[0034] A significant feature of the magnetic head 200 of the presentinvention is the simultaneous fabrication of the upper helical coiltraces 184 and the vertical coil interconnect liens 180, such that theupper helical coil traces 184 and the interconnects 180 are integrallyformed in one process step. This single step fabrication process isenabled through the use of an RIE etch process that simultaneouslycreates the trenches 160 of the upper helical coil traces and thevertical vias 164 for the interconnects 180. The patterned etch stoplayer 120 that is deposited on top of the yoke is a significantstructural element in halting the RIE etching above the yoke, and theetch stop layer 120 thus serves as an electrical insulation layerbetween the subsequently deposited upper coil traces and the yoke. Ifthis single step fabrication process is not utilized, then the vias mustbe created and plated up, followed by the alignment of a mask for theupper coil traces, and the separate trench formation and plating up ofthe upper coil traces. Therefore, because the upper coil traces and thevertical interconnects are fabricated in a single RIE etch step, theoverall fabrication of the device is simplified over prior art helicalcoil fabrication processes in which the vertical interconnects arefabricated separately from the upper helical coil traces. Thefabrication method of the present invention therefore facilitates thecreation of a magnetic head 200 having a fine pitch helical coil in afabrication process that is more easily and efficiently accomplished,and which therefore produces a higher product yield. Because the helicalcoil facilitates the use of a shorter yoke within the magnetic head 200,the magnetic flux rise time of the magnetic head is decreased and thedata writing rate of the magnetic head is increased.

[0035] While the present invention has been shown and described withregard to certain preferred embodiments, it is to be understood thatthose skilled in the art will develop certain alterations andmodifications thereto. It is therefore intended that the followingclaims cover all such alterations and modifications that neverthelessinclude the true spirit and scope of the invention.

What is claimed is:
 1. A magnetic head, comprising: a first magneticpole; a write gap layer being disposed upon said first magnetic pole; asecond magnetic pole including a yoke member; an induction coil beinghelically formed around said yoke member, said helical coil including, aplurality of lower helical coil traces being formed below said yokemember; a plurality of upper helical coil traces being formed above saidyoke member; a plurality of vertical interconnect members being formedbetween said lower helical coil traces and said upper helical coiltraces, wherein said interconnect members are integrally formed withupper helical coil traces.
 2. A magnetic head as described in claim 1wherein each upper helical coil trace is integrally formed with at leastone vertical interconnect member.
 3. A magnetic head as described inclaim 1 wherein said yoke member is formed with side edges, and whereinsaid vertical interconnects are formed outside of said side edges ofsaid yoke member.
 4. A magnetic head as described in claim 1 whereinsaid induction coil is composed of copper.
 5. A magnetic head asdescribed in claim 1 wherein said induction coil is formed usingelectroplating fabrication techniques.
 6. A magnetic head as describedin claim 1 wherein a first insulation layer is formed between said lowerhelical coil traces and said yoke member, and a second insulator layeris formed between said yoke and said upper helical coil traces, andwherein said second insulator layer is composed of a material thatdiffers from the material of said first insulator layer, such that saidsecond insulator layer acts as an etch stop layer in a reactive ion etch(RIE) step, whereas said first insulation layer is etched in said RIEetch step.
 7. A magnetic head as described in claim 1 wherein said upperhelical coil traces and said vertical interconnect lines are plated intotrenches and vias that are formed in a single reactive ion etch (RIE)process step.
 8. A magnetic head, comprising: a first magnetic polelayer; a write gap layer being formed on said first magnetic pole layer;a P2 pole tip being formed in a pole tip layer on said write gap layer;a plurality of lower helical coil traces being formed in said pole tiplayer; an insulator layer being formed on said lower coil traces; a yokeportion of the P2 pole being formed on said insulation layer, said yokehaving lateral side edges, and being formed such that end portions ofsaid lower helical coil traces extend outward beyond said lateral edgesof said yoke; an insulation layer being formed on top of said yoke; aplurality of upper helical coil traces being formed on top of saidinsulator layer, such that lateral ends of said upper helical coiltraces project outward above said lateral end portions of said lowerhelical coil traces; a plurality of vertical interconnect lines beingformed between said projecting ends of said upper helical coil tracesand said projecting ends of said lower helical coil traces, wherein saidupper helical coil traces and said vertical interconnect lines areintegrally formed.
 9. A magnetic head as described in claim 8 whereineach upper helical coil trace member is integrally formed with at leastone vertical interconnect line.
 10. A magnetic head as described inclaim 9 wherein said yoke is formed with side edges, and wherein saidvertical interconnect lines are formed outside of said side edges ofsaid yoke.
 11. A magnetic head as described in claim 10 wherein saidinduction coil is composed of copper.
 12. A magnetic head as describedin claim 11 wherein said induction coil is formed using electroplatingfabrication techniques.
 13. A magnetic head as described in claim 12wherein a first insulator layer is formed between said lower helicalcoil traces and said yoke, and a second insulator layer is formedbetween said member and said upper helical coil traces, and wherein saidsecond insulator layer is composed of a material that differs from thematerial of said first insulation layer, such that said second insulatorlayer acts as an etch stop layer in a reactive ion etch (RIE) step,whereas said first insulation layer is etched in said RIE etch step. 14.A magnetic head as described in claim 13 wherein said upper helical coiltraces and said vertical interconnect lines are plated into trenches andvias that are formed in a single reactive ion etch (RIE) process step.15. A method for forming a magnetic head, comprising the steps of:forming a first magnetic pole upon an insulator layer; forming a writegap layer upon said first magnetic pole; forming a plurality of lowerhelical coil traces upon said write gap layer; forming a yoke portion ofa second magnetic pole above said lower helical coil traces; forming aplurality of upper helical coil traces above said yoke, and forming aplurality of vertical interconnect lines between said upper helical coiltraces and said lower helical coil traces, wherein said upper helicalcoil traces and said vertical interconnect lines are fabricated in asingle process step, such that they are integrally formed; whereby saidlower helical coil traces, said vertical interconnect lines and saidupper helical coil traces are electrically connected to form a helicalcoil that surrounds said yoke.
 16. A method for fabricating a magnetichead as described in claim 15 including the further steps of forming anetch stop layer upon said yoke and forming trenches and vias utilizing areactive ion etch (RIE) process step to fabricate said upper coil tracesand said interconnect lines.
 17. A method for fabricating a magnetichead as described in claim 16 including the further steps of forming aninsulation layer upon said lower helical coil traces and beneath saidyoke.
 18. A hard disk drive comprising: at least one hard disk beingadapted for rotary motion upon a disk drive; at least one slider devicehaving a slider body portion being adapted to fly over said hard disk; amagnetic head being formed on said slider body for writing data on saidhard disk, said magnetic head including: a first magnetic pole; a writegap layer being disposed upon said first magnetic pole; a secondmagnetic pole including a yoke member; an induction coil being helicallyformed around said yoke member, said helical coil including, a pluralityof lower helical coil traces being formed below said yoke member; aplurality of upper helical coil traces being formed above said yokemember; a plurality of vertical interconnect members being formedbetween said lower helical coil traces and said upper helical coiltraces, wherein said interconnect members are integrally formed withupper helical coil traces.
 19. A hard disk drive as described in claim18 wherein each upper helical coil trace member is integrally formedwith at least one vertical interconnect member.
 20. A hard disk drive asdescribed in claim 18 wherein said yoke member is formed with sideedges, and wherein said vertical interconnects are formed outside ofsaid side edges of said yoke member.
 21. A hard disk drive as describedin claim 18 wherein said induction coil is composed of copper.
 22. Ahard disk drive as described in claim 18 wherein said induction coil isformed using electroplating fabrication techniques.
 23. A hard diskdrive as described in claim 18 wherein a first insulation layer isformed between said lower helical coil traces and said yoke member, anda second insulator layer is formed between said yoke member and saidupper helical coil traces, and wherein said second insulator layer iscomposed of a material that differs from the material of said firstinsulation layer, such that said second insulation layer acts as an etchstop layer in a reactive ion etch (RIE) step, whereas said firstinsulation layer is etched in said RIE etch step.
 24. A hard disk driveas described in claim 18 wherein said upper helical coil traces and saidvertical interconnects are plated into trenches and vias that are formedin a single reactive ion etch (RIE) process step.